1. Field of the Invention
This invention relates to power and energy measurement systems and methods, and more particularly to single phase bi-directional power and energy systems and methods which are configured on a single semiconductor chip.
2. Description of the Related Art
Power and energy measurement systems of many kinds are well-known. Many of such systems are electromechanical. Many of such systems are inaccurate. Some of such systems consume excessive power.
There is a need for accurate power and energy measurement systems having enhanced functionality, which are nonetheless inexpensive and which consume reduced energy levels to operate.
According to the present invention, phase compensation is implemented with a reduced number of registers. According to the present invention, a SINC filter is used to provide a selectable variable delay. According to one embodiment of the present invention, a SINC filter includes first and second stages. A first stage includes an integrator operating at a high signal sampling rate. The output of the integrator is connected to a differentiator or a comb, which operates at a lower rate of signal sampling. According to one embodiment of the present invention, the integrator sampling rate is at least twice the differentiator or comb sampling rate. The time of sampling by the comb is controlled by a comparator output, which actuates when the content of a writeable register, written to/from a controller, is equal to the output of a divide counter. The divide counter is the second stage of a divider system including first and second divide-by-eight dividers.
According to one embodiment of the present invention, a power and energy measurement system of enhanced accuracy performs a plurality of functions including energy and power measurement, root mean square voltage and root mean square current determination, and energy to pulse-rate conversion. The measurement system has reduced power consumption and an interface which is optimized for operation with a shunt sensor. The measurement system includes a phase compensation system and operates with ground-referenced signals and a single power supply. The system further has a calibration system including a feature for providing a settable offset useful for determining power level calculations.